When most people think of big cats, they picture Africa or Asia, but the South American jaguar is the third-largest feline in the world, behind only the tiger and lion. While people often use the term jaguar and leopard interchangeably, they are actually two different but closely related species. Jaguars are the only species from the genus Panthera to survive in the New World (North and South America) and their ancestors were believed to have emigrated from Asia. Despite geographical proximity and a superficial likeness, cougars are not related to jaguars and are in a different genus. Jaguars, like lions, tigers, and leopards, are considered 'big cats' and one of the main things that sets them apart is the ability to roar, however some definitions of big cats allows for non-roaring species such as cougars, clouded leopards, and cheetahs simply for their size.